It has been previously known to utilize one or several venturis as an outlet from spray painting booths, for instance, for spray painting automobile chassis. The venturis may be suitably disposed directly below or even at some distance from a grate-like floor, through which polluted conditioning air may pass to be funneled through said venturi, in which the air speed is increased considerably bringing about the special effect, that paint particles agglomerate and can be more easily taken care of in a subsequent separation procedure. According to usual practice water is circulated under substantially the entire grate-like floor and through the venturi, so that it is not stopped up by paint. The flowing water is conveyed through a collection chamber, wherefrom water is recirculated again to a reservoir or other receiver under said grate-like floor. Also the air can all or partly be recirculated.
In principle, such known solutions function satisfactorily to remove the pollutants, but present difficulties in cleaning the apparatus and produce a high-noise level, which can be very troublesome. Modifications reducing the noise level increase the difficulty in cleaning, and vice-versa. These factors can oppose one another and often do so, since a unit with a greater noise-muffling effect as a rule is difficult to clean, while a unit which is easily cleaned as a rule has a very high production of noise. Even in units having a lower production of noise, and even with impaired facility for cleaning, the noise is so high that it is troublesome for personnel must spend time in the spray painting booth or other work space being ventilated.